The subject of the present disclosure relates generally to gas/liquid separators or gas/liquid/solid separators. Separators of this type are typically vessels that may be operated at atmospheric or above atmospheric pressures.
The main function of a cyclonic separator system is to segregate immiscible phases of a process stream, such as when a process stream comprises a mixed liquid phase and gas phase. Such separator systems utilize cyclonic chambers installed inside a pressure vessel. An inlet and a manifold chamber leads from the outside of the pressure vessel to the entrance to each of the cyclonic chambers. A typical cyclonic separator may employ one or more cyclonic chambers, depending on the application and the capacity required, as illustrated in FIG. 7.
Separator systems are commonly used in the oil and gas industry to, for example, separate immiscible entrained gases from a liquid phase of a mixed gas/liquid process stream, wherein the process stream enters the pressure vessel through an inlet manifold chamber, and from there enters the individual cyclonic chambers through inlets that are tangential to the curvature of each of the cyclonic chambers. As a result of the velocity and the tangential angle at which the liquid/gas process stream enters the cyclonic chamber, centrifugal forces act on the process stream and cause it to spin around the curvature of the cyclonic chamber.
Centrifugal forces acting on each of the immiscible phases in the process stream, cause the phases to move either away from or towards the centre of the cyclonic chamber. A difference in the mass and densities of phases of the process stream cause the heavier phases (such as the one or more liquids of the liquid phase) to coalesce on the inner wall of the cyclonic chamber and travel in a downwards direction through the cyclonic chamber due to the force of gravity, while the lighter, or gaseous, phase(s) of the gas phase tend to remain closer to the centre of the cyclonic chamber forming a central upward moving column of lighter phase that exit through an aperture positioned in the upper covering of the cyclonic chamber.
To ensure effective light/heavy phase separation, the incoming process stream needs to flow at a higher velocity to create a greater centrifugal force for separation of the heavier phase from the lighter phase. As well, the gas outlet aperture must be designed to a minimum size based on how much lighter phase is being separated out. There are further limits to the design of the tangential inlets to each of the cyclonic chambers to create the desired high momentum and flow rate of the incoming process fluid. When this high momentum incoming processes stream enters the cyclonic chamber, there tends to be a pressure drop and corresponding fluid expansion of the process stream.
When the inlet process stream expands upon entry, it is limited in expanding outwardly by the sidewalls of the cyclonic chamber cylindrical tube, so there is a tendency for the process stream, containing both a heavy and light phase, to expand into the central upward moving column of light phase, thereby undesirably resulting in at least some entrainment of liquid phase(s) in the exiting gaseous phase(s). Furthermore, with high flow rate and velocity of the process stream entering the cyclonic chamber tubes, often the momentum of the fluid is greater than the force of gravity acting on the heavier liquid phase being separated, preventing some of the heavier, liquid phase from flowing down to the liquid outlet. This leads to heavier, liquid phase being present in the cyclonic chamber and a greater chance of the heavier phases crossing over into the central upward moving column of lighter, gas phase.
Typically to overcome this type of one must either operate the cyclonic separator at a lower flow rate, thus reducing the volume of a process stream that may be separated in a given timeframe, or design larger cyclonic chamber volume to meet capacity requirements for separating a liquid/gas process stream.
As illustrated in FIG. 7, a common design for a prior art cyclonic separator 100 is comprised of multiple cyclonic chambers 104 in fluid communication with an inlet manifold 106 through a tangential inlet 102. A process stream enters the inlet manifold 106 through the entrance 108 and travels in direction A through the inlet manifold 106. As the process stream travels through the inlet manifold 106, portions of the process stream are forced through the tangential inlet 102 of each of the eight cyclonic chambers 104, wherein the momentum and flowrate of the flowing portion of the process stream, upon impact against the inner surface 110 of the cyclonic chamber 104 causes the process stream to splash through the gas outlet of the cyclonic chamber 104. This results in a failure mode of the cyclonic separator 100 as the lighter, or gaseous, phases of the process stream exiting the cyclonic chamber 104 becomes contaminated with the heavier, or liquid, phases of the process stream, thereby reducing the efficiency of separation of the heavier and lighter phases of the process stream.
In the prior art, when this type of failure mode occurs, one must modify the operation of the cyclonic separator 100 such as reducing the flow rate of the incoming process stream or the flow rate of the exiting lighter, gaseous phases of the process stream, so as to reduce the flow rate or volume of process stream entering the tangential inlet 102 of the cyclonic chamber 104. As such, there is a need for an improved design of a cyclonic separator that will improve the efficiency and capacity for separation of a gas phase from a liquid phase in a mixed process stream.